| 1. |
- Casolino, M., et al.
(författare)
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Cosmic-ray observations of the heliosphere with the PAMELA experiment
- 2006
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Ingår i: Astrophysics. - : Elsevier BV. ; , s. 1848-1852
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Konferensbidrag (refereegranskat)abstract
- The PAMELA experiment is a multi-purpose apparatus built around a permanent magnet spectrometer, with the main goal of studying in detail the antiparticle component of cosmic rays. The apparatus will be carried in space by means of a Russian satellite, due to launch in 2005, for a three year-long mission. The characteristics of the detectors composing the instrument, alongside the long lifetime of the mission and the orbital characteristics of the satellite, will allow to address several items of cosmic-ray physics. In this paper, we will focus on the solar and heliospheric observation capabilities of PAMELA.
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| 2. |
- Adriani, O., et al.
(författare)
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Measurements of quasi-trapped electron and positron fluxes with PAMELA
- 2009
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 114, s. A12218-
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents precise measurements of the differential energy spectra of quasi-trapped secondary electrons and positrons and their ratio between 80 MeV and 10 GeV in the near-equatorial region (altitudes between 350 km and 600 km). Latitudinal dependences of the spectra are analyzed in detail. The results were obtained from July until November 2006 onboard the Resurs-DK satellite by the PAMELA spectrometer, a general purpose cosmic ray detector system built around a permanent magnet spectrometer and a silicon-tungsten calorimeter.
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| 3. |
- Adriani, O., et al.
(författare)
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Time Dependence Of The Proton Flux Measured By Pamela During The 2006 July-2009 December Solar Minimum
- 2013
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Ingår i: Astrophysical Journal. - : IOP Publishing. - 0004-637X .- 1538-4357. ; 765:2, s. 91-
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Tidskriftsartikel (refereegranskat)abstract
- The energy spectra of galactic cosmic rays carry fundamental information regarding their origin and propagation. These spectra, when measured near Earth, are significantly affected by the solar magnetic field. A comprehensive description of the cosmic radiation must therefore include the transport and modulation of cosmic rays inside the heliosphere. During the end of the last decade, the Sun underwent a peculiarly long quiet phase well suited to study modulation processes. In this paper we present proton spectra measured from 2006 July to 2009 December by PAMELA. The large collected statistics of protons allowed the time variation to be followed on a nearly monthly basis down to 400 MV. Data are compared with a state-of-the-art three-dimensional model of solar modulation.
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| 4. |
- Bongi, M, et al.
(författare)
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PAMELA : A satellite experiment for antiparticles measurement in cosmic rays
- 2004
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 51:3, s. 854-859
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Tidskriftsartikel (refereegranskat)abstract
- PAMELA is a satellite-borne experiment that will study the antiproton and positron fluxes in cosmic rays in a wide range of energy (from 80 MeV up to 190 GeV for antiprotons and from 50 MeV up to 270 GeV for positrons) and with high statistics, and that will measure the antihelium/helium ratio with a sensitivity of the order of 10(-8). The detector will fly on-board a polar orbiting Resurs DK1 satellite, which will be launched into space by a Soyuz rocket in 2004 from Baikonur cosmodrome in Kazakhstan, for a 3-year-long mission. Particle identification and energy measurements are performed in the PAMELA apparatus using the following subdetectors: a magnetic spectrometer made up of a permanent magnet equipped with double-sided microstrip silicon detectors, an electromagnetic imaging calorimeter composed of layers of tungsten absorber and silicon detectors planes, a transition radiation detector made of straw tubes interleaved with carbon fiber radiators, a plastic scintillator time-of-flight and trigger system, a set of anticounter plastic scintillator detectors, and a neutron detector. The features of the detectors and the main results obtained in beam test sessions are presented.
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| 5. |
- Munini, R., et al.
(författare)
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Evidence of Energy and Charge Sign Dependence of the Recovery Time for the 2006 December Forbush Event Measured by the PAMELA Experiment
- 2018
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Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 853:1
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Tidskriftsartikel (refereegranskat)abstract
- New results on the short-term galactic cosmic-ray (GCR) intensity variation (Forbish decrease) in 2006 December measured by the PAMELA instrument are presented. Forbush decreases are sudden suppressions of the GCR intensities, which are associated with the passage of interplanetary transients such as shocks and interplanetary coronal mass ejections (ICMEs). Most of the past measurements of this phenomenon were carried out with groundbased detectors such as neutron monitors or muon telescopes. These techniques allow only the indirect detection of the overall GCR intensity over an integrated energy range. For the first time, thanks to the unique features of the PAMELA magnetic spectrometer, the Forbush decrease, commencing on 2006 December 14 and following a CME at the Sun on 2006 December 13, was studied in a wide rigidity range (0.4-20 GV) and for different species of GCRs detected directly in space. The daily averaged GCR proton intensity was used to investigate the rigidity dependence of the amplitude and the recovery time of the Forbush decrease. Additionally, for the first time, the temporal variations in the helium and electron intensities during a Forbush decrease were studied. Interestingly, the temporal evolutions of the helium and proton intensities during the Forbush decrease were found to be in good agreement, while the low rigidity electrons (<2 GV) displayed a faster recovery. This difference in the electron recovery is interpreted as a charge sign dependence introduced by drift motions experienced by the GCRs during their propagation through the heliosphere.
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| 6. |
- Munini, R., et al.
(författare)
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Short-term variation in the galactic cosmic ray intensity measured with the PAMELA experiment
- 2017
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- New results on the galactic cosmic ray (GCR) short-term intensity variation associated with Forbush decrease and co-rotating interaction regions (CIRs) measured by the PAMELA instrument between November 2006 and March 2007 are presented. Most of the past measurements on Forbush decrease events were carried out with neutron monitor detector. This tecnique allows only indirect detection of the overall GCR intensity over an integrated energy range. For the first time, thanks to the unique features of the PAMELA magnetic spectrometer, the Forbush decrease associated with the December 13th coronal mass ejection (CME) was studied in a wide rigidity range (0.4 - 20 GV) and for different species of GCRs detected directly in space. Using GCR protons, the amplitude and the recovery time of the Forbush decrease were studied for ten rigidity interval with a temporal resolution of one day. For comparison the helium and the electron intensity over time were also studied. The temporal evolution of the helium and proton intensity was found in good agreement while the electrons show, on average, a faster recovery time. This was interpreted as a charge-sign dependence introduced by drift motion experienced by the low rigidity (< 5 GV) GCRs during their propagation through the heliosphere. Moreover a clear 13.5 days cyclical variation was observed in the GCR proton intensity after the Forbush decrease. This phenomena could be interpreted as an effect of prominent structures of compressed plasma in the solar wind, i.e. CIRs, or to the latitudinal gradient due to the crossing of the heliospheric current sheet (HCS).
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| 7. |
- Stozhkov, Y. I., et al.
(författare)
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About Separation of Hadron and Electromagnetic Cascades in the Pamela Calorimeter
- 2005
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Ingår i: International Journal of Modern Physics A. - 0217-751X .- 1793-656X. ; 20:29, s. 6745-6748
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Tidskriftsartikel (refereegranskat)abstract
- Results of calibration of the PAMELA instrument at the CERN facilities are discussed. In September, 2003, the calibration of the Neutron Detector together with the Calorimeter was performed with the CERN beams of electrons and protons with energies of 20-180 GeV. The implementation of the Neutron Detector increases a rejection factor of hadrons from electrons about ten times. The results of calibration are in agreement with calculations.
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| 8. |
- Adriani, O., et al.
(författare)
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Cosmic-Ray Electron Flux Measured by the PAMELA Experiment between 1 and 625 GeV
- 2011
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 106:20, s. 201101-
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Tidskriftsartikel (refereegranskat)abstract
- Precision measurements of the electron component in the cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy. Here we present new results regarding negatively charged electrons between 1 and 625 GeV performed by the satellite-borne experiment PAMELA. This is the first time that cosmic-ray e(-) have been identified above 50 GeV. The electron spectrum can be described with a single power-law energy dependence with spectral index -3.18 +/- 0.05 above the energy region influenced by the solar wind (> 30 GeV). No significant spectral features are observed and the data can be interpreted in terms of conventional diffusive propagation models. However, the data are also consistent with models including new cosmic-ray sources that could explain the rise in the positron fraction.
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| 9. |
- Adriani, O., et al.
(författare)
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Cosmic-Ray Positron Energy Spectrum Measured by PAMELA
- 2013
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 111:8, s. 081102-
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Tidskriftsartikel (refereegranskat)abstract
- Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24 500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.
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| 10. |
- Adriani, O., et al.
(författare)
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Measurement of the flux of primary cosmic ray antiprotons with energies of 60 MeV to 350 GeV in the PAMELA experiment
- 2013
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Ingår i: JETP Letters. - 0021-3640 .- 1090-6487. ; 96:10, s. 621-627
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Tidskriftsartikel (refereegranskat)abstract
- It is interesting to measure the antiproton galactic component in cosmic rays in order to study the mechanisms by which particles and antiparticles are generated and propagate in the Galaxy and to search for new sources of, e.g., annihilation or decay of dark matter hypothetical particles. The antiproton spectrum and the ratio of the fluxes of primary cosmic ray antiprotons to protons with energies of 60 MeV to 350 GeV found from the data obtained from June 2006 to January 2010 in the PAMELA experiment are presented. The usage of the advanced data processing method based on the data classification mathematical model made it possible to increase statistics and analyze the region of higher energies than in the earlier works.
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